Intravenous apparatus and method

ABSTRACT

A method and apparatus for inserting and monitoring the placement of a cannula tip within a peripheral vein of a human body where the cannula includes a sensor located at predetermined location and mounted on the cannula for sensing the biological material of the body to guide the insertion of the cannula tip into the vein and alerts to the withdrawal of the cannula tip from the vein in the body.

CROSS REFERENCE TO RELATED APPLICATION

This patent application is a continuation-in-part of U.S. patentapplication Ser. No. 13/526,303, filed on 18 Jun. 2012. The co-pendingparent application is hereby incorporated by reference herein in itsentirety and is made a part hereof, including but not limited to thoseportions which specifically appear hereinafter.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an intravenous apparatus and method, and moreparticular, to an intelligent intravenous apparatus and method fordetecting a problem with a catheter tip placement or withdrawal in andfrom a vein for infusion of intravenous (IV) fluids.

2. Discussion of Related Art

Certain emergency circumstances demand immediate intravenous therapy forpatients facing life threatening loss of bodily fluids due to accidentsor other critical care applications found in emergency centers or incritical care facilities of a hospital. IV therapy requires the infusionof liquid substances directly into a vein of the patient. Typically, IVfluids in a bag suspended from an IV pole employing a drip chamber thatis connected to a peripheral IV line which consists of a short catheterinserted through the skin into a peripheral vein outside of the chest orabdomen. This is usually in the form of a cannula-over-needle apparatus,in which a flexible plastic or polymer cannula comes mounted on a metaltrocar. Once the tip of the needle and cannula are located properly inthe vein, the trocar is withdrawn and discarded. Meanwhile, the cannulais advanced inside the vein to a predetermined position where anexternal hub or valve area of the catheter is secured to the patient'sbody by medical tape or the like to hold it in place. Blood is oftenwithdrawn at the time of the initial insertion of the cannula into thepatient's vein. This is the most common intravenous access method usedin both hospitals and in the field by paramedics or emergency medicaltechnicians (EMTs).

The calibers of cannula generally range from 12 to 26 gauge with 12being the largest and 26 being the smallest. The part of the catheterremaining outside of the skin is called the IV connecting hub or IVvalve that is connected to the IV lines back to the IV hag of fluids.For example, an all-purposes IV cannula for infusions and blood drawsmight be an 18 and 20 gauge sized cannula manufactured by BD/BectonDickinson Infusion Therapy AB. This intravenous cannula comes with aninner needle that is removed once the flexible portion of the cannula isfully inserted into the patient's vein.

Due to the different skill levels of the medical personnel inserting theIV cannula into the peripheral vein of a patient's hand or arm,complications sometimes develop in a number of the patients receiving IVfluid therapy from infiltration. This is a condition where throughimproper insertion or withdrawal of the cannula either into or from aperipheral vein, respectfully, results in IV fluids leaking into thesurrounding tissues around the vein causing a potential serious healthcondition known as infiltration.

Before the blood is withdrawn at the time of insertion, this is also thetime to detect whether the cannula portion of the catheter is beingproperly inserted in the patient's vein or not. If the cannula is notsited properly or the vein is missed or even pierced where the cannulagoes through the vein and enters into the surrounding subcutaneoustissue rather than remaining in the vein, complications may develop forthe patient receiving the IV fluid therapy. Many serious complicationscan result from improper cannula insertion into the vein. The potentialcomplications include edema causing tissue damage or may even includenecrosis depending on the medication or fluid being infused. Thisextravasation is a leakage of infused fluids into the vasculature of thesubcutaneous tissue surrounding the vein. The leakage of high osmoticsolutions or chemotherapy fluids can result in significant tissuedestruction or other complications. Therefore, in an emergency room of ahospital where interns or nurses are treating a patient by administeringfluids intravenously, it becomes a critical factor in the safety of thepatient that IV fluids are indeed flowing into the vein of the patientand not into the surrounding tissue. Insertions of a cannula by EMTs inthe field at accident scenes who need to administer IV fluid therapy toan injured party are a critical application where the cannula needs tobe inserted properly into the vein and to remain within the vein duringtransportation to the hospital to prevent a loss of life.

However, due to human error, mistakes are bound to be made whileinserting the cannula into a vein or the vein is missed altogetherduring the initial insertion of the needle/cannula. Other times due tomovement of the patient by medical personnel or by the patientthemselves, the cannula begins to withdraw from the vein. To avoid thischronic problem or other problems during insertion of the needle throughthe skin into the vein, the medical staff needs some indication aboutthe successful insertion of the needle and cannula into the patient'speripheral vein. The medical personnel also need a convenient way tomonitor and then to be alerted to any withdrawal of the cannula from thevein during IV fluid treatment.

To solve this problem of cannula tip placement and to reduce theincidents of infiltration of IV fluids into the surrounding tissuesinstead of the vein, the intern, nurse or EMT tasked with the needleinsertion into a patient's vein to start the IV therapy would greatly behelped by knowing that their insertion of the cannula into theperipheral vein is being accomplished successfully by some type offeedback signal indicating that the proper insertion of the cannula tipwithin the vein of a patient has occurred.

To solve the problem of infiltration after the initial insertion of thecannula into the patient's vein when the cannula tube backs out of thevein or begins to leak for various reasons, a variety of complex leakdetectors have been proposed for detecting a leak or an extravasation ofa liquid injected through a needle into a blood vessel of a human body,as described, for example, in U.S. Pat. Nos. 7,546,776, 6,408,204,5,964,703, 5,947,910, 6,375,624, 5,954,668, 5,334,141, 4,647,281, and4,877,034. Still other U.S. Pat. Nos. 6,408,204, 5,964,703, 5,947,910disclose complex leak detectors for detecting a leaking liquid due to achange in impedance on the skin surface of a human body; U.S. Pat. Nos.6,375,624, 5,954,668, 5,334,141, 4,647,281 disclose leak detectors fordetecting a leaking liquid from a change in temperature of a humanorgan; and U.S. Pat. Nos. 8,078,261 and 4,877,034 disclose alight-guided catheter and leak detector for placement through the skinand for detecting a leaking liquid from a change in opticalcharacteristics of the blood, respectively. There are a number ofvarious prior art solutions to the infiltration problem that centeraround the monitoring of the pressures of the IV fluids administered tothe patient. The pressure information is used to control the flow of theIV fluids. Examples of pressure monitoring systems are shown in U.S.Pat. Nos. 4,277,227; 4,457,751; 4,534,756; 4,648,869 and 7,169,107.

However, none of these prior art patents teach a highly reliableportable apparatus and method of guiding a catheter into a vein and thendetecting the proper insertion of the IV cannula of the catheter duringits insertion into the patient's peripheral vein by providing a feedbacksignal either visual or audible for the intern, nurse or EMT startingthe IV therapy. Moreover, this smart IV catheter is highly portable andcapable of being used in emergency situations outside of a doctor'soffice or hospital setting in field emergency situations by EMTs priorto the patient being taken by ambulance to the hospital's emergencyroom.

Most of these prior art infusion detection systems referred to abovewhile doing a good job in detecting problems once the TV therapy begins,the prior art systems do not monitor the initial insertion of the IVcannula into the vein to make sure the cannula is properly inserted intothe patient's vein. Some of the prior art systems even require asubstantial infusion of IV liquids prior to even detecting a leakagesuch as a leakage that occurs when the cannula pulls out of thepatient's vein. In short, all of these systems are rather complicatedand therefore require expensive pieces of equipment that are notnecessarily readily available to paramedics or EMTs in the field whomust start the IV therapy to an injured patient at an accident scene oreven immediately available to the nurses, interns or EMTs even in ahospital emergency room setting.

SUMMARY OF THE INVENTION

A sharp, pointed rod or trocar fits inside a cannula or the softcatheter tube and the sharp point pierces the skin and is directed intoa predetermined vein of the patient by the medical technician or doctor.The trocar is then withdrawn. A sensor generally located within thehollow tubing of the flexible or rigid cannula detects a drop in theimpedance as blood flows across the surface of the cannula. The sensoris usually embedded within the polymer material of the cannula thatprotects it from being damaged when it pierces the skin and enters intothe patient's vein. The sensors and the wire connections are generallyembedded in the polymer material during the manufacturing and extrusionprocess or later after the extrusion process the sensors and wire aredeposited on the cannula surface and properly covered by a thin skinmaterial to prevent damage or dislocation from the cannula along withany wire connections extending back to a module for processing thesensed signal. The sensor(s) then send an electrical signal back to themodule for either a visual display or audible sound indication of propercannula insertion within the patient's vein. The module may take severalshapes and have a predetermined thickness and shape in order to house apower source, processing electronics, a soft button switch or similardevice for initiating the device when taken out of its package for thefirst time to be used on a patient. The processing electronics in themodule receives the input signal from the sensor(s) and then generatesan output signal that fires a light emitting diode (LED) display or inaddition, fires a piezo-electric buzzer horn along with the lightindication so the medical technician gets both a light and a soundindication of proper insertion of the cannula into a patient's vein.

In one embodiment, an intravenous catheter for guiding tip placementinto a peripheral vein of a body and monitoring any tip removal from theperipheral vein, comprises:

a flexible plastic, tubular cannula having a tip at the distal end forinsertion into a peripheral vein of a body and a hub at the opposite endfor attachment to an IV bag;

a sensor mounted within the cross section of the cannula at apredetermined location thereon, or at the hub, for sensing an impedanceof a sensed biological material in the body including the blood and thengenerating an output signal representative of a sensed biologicalmaterial;

processor and modulation circuitry connected to the output signal forreceiving and then generating a display or audible sound representingthe location of the cannula tip within the biological material beingsensed in the body during insertion of the cannula or upon thewithdrawal of the cannula from the body; and wherein the displayprovides a feedback to a physician or medical personnel for correctcatheter tip placement in the peripheral vein of the patient and whereinthe display provides an alert to shut off the infusate when the tipdislodges from the vein but remains in the body to avoid infiltrationinto the subcutaneous tissues of the body.

In brilliant sunlight, the sound indicator that varies in soundaccording to state of properly inserting the cannula into a vein isoften more useful to overcome the washed out LED display under brilliantsunlight conditions. In a portable unit of the apparatus, the circuitryto process the signals from the sensor(s), drive the LED display andpiezo buzzer are preferably contained within a single applicationspecific integrated chip (ASIC) or other suitable miniaturized circuitrymounted within the module or mounted to the catheter itself.

In another preferred embodiment, the module includes an initiationswitch activated when peeling back a suitable protective cover over anadhesive backing to the module used to securely attach the module to theskin of a hand or forearm of the patient once the cannula is properlyinserted into the peripheral vein of the patient. Also, a soft or domeswitch accessible on the non-adhesive topside of the module couldprovide multiple functions to be described later in greater detail. Thisdome switch is also a source for the initial activation of the moduleand the processing and modulation circuitry when pressed for the firsttime.

Because of the miniaturization of electronic circuitry today, the modulemight be integrated or mounted in close proximity to the hub or IV valveon the catheter. The module might also be connected via a wire ofpredetermined length from the catheter to the module mounted on the handor forearm of a patient receiving the IV therapy. The signal might eventravel either by a wired connection or a wireless connection from themodule back to a monitoring station located on either an IV cart, IVpole or other base station located in any predetermined location such asin the patient hospital room, in a hospital emergency room or even in apatient's doctor office. The wireless communication for the device ofthe present invention includes the use of radio frequencies (RF) likeBluetooth which is a proprietary open wireless technology standard forexchanging data over short distances (using short-wavelength radiotransmissions in the ISM band from 2400-2480 MHz) from fixed or mobiledevices. This allows a hospital to create personal area networks (PANs)with high levels of security within the hospital where up to seven suchdevices are capable of being connected to the same base station. AnotherRF connection available for the device of the present invention is aWiFi connection for a sensing module to receive and then output theprocessed sensor signal to a potential receiving base station similar toa cellular base station in 3g or 4g communications or Wi-Fi connection.The Wi-Fi technology allows either the sensors or the module to exchangedata wirelessly using the radio waves over a computer network, includinghigh-speed Internet connections. Wi-Fi as any wireless local areanetwork (WLAN) product are generally based on the Institute ofElectrical and Electronics (IEEE) 802.11 standards. The presentinvention incorporates both the Bluetooth and WiFi standards in itssmart IV Catheter design. These communication networks allow the use ofpasswords for security purposes.

So the portable IV Catheter/Cannula manufactured according to thepresent invention includes a multi-functional module that receivessignals from the sensors mounted within or on the surface of the cannulaand then sends the sensor signals as an input to the sensing module forprocessing or the sensor signals are sent back to a base station via ahardwired connection or wireless connections of either a Bluetooth or aWiFi connection for processing and displaying the outcome. Theelectronic circuitry within the sensing module or within the basestation then processes the sensor signals for generating output signalsto drive the LED display or piezo buzzer for indicating the successfulinsertion of the cannula into the patient's peripheral vein.

The LED is preferably capable of indicating at least several states.When the needle is first being inserted into the skin, the LED woulddisplay a flashing red color that progresses to a steady red as thecannula is inserted further under the skin. As the cannula progressesunder the skin to the surface of the vein, a flashing yellow would beseen before the flashing yellow changed to a steady yellow. Finally, thesteady yellow would change to a flashing green and then a steady greenlight when the cannula is fully inserted into the vein and all of thesensors detect the flow of blood within the vein. The changes of colorsare directly correlated to the drop in impedance as the sensors locatedwithin or on the surface of the cannula sense the condition of a bloodflow in the vein. If the cannula is not properly inserted within thevein, the EMT will see a red or flashing red indication from the LEDand/or a beeping sound from the Piezo Buzzer related to a pattern ofsounds to indicate that it is not properly inserted within the vein.

Once the doctor, intern, nurse or EMT has properly inserted the cannulawithin the vein, the display of LED or sound from the Piezo Buzzerprovides predetermined signals from light or sound that indicate thatthe cannula is sited properly within the vein. The indication may be onthe module unit and/or patch attached to the hand or forearm and/or on adisplay back at the base station located at the IV pole or other area inproximity to the doctor, intern, nurse or EMT personnel inserting the IVcannula into the patient's peripheral vein. The signal indications areused to properly guide the hand of the caretaker or medical professionalto make sure the IV cannula is inserted within the vein of the patientand not into the subcutaneous tissue surrounding the vein. The signalsfrom the sensor(s) spaced a predetermined distance apart from oneanother which are located within the wall or on surface of the flexiblepolymer cannula tube along its longitudinal axis from its distal end togenerally in close proximity to the end connected to the hub of thecannula show the change of impedance as the cannula is positioned withinthe vein. The sensors detect the presence or absence of the blood in andaround the cannula inserted within the vein at each sensor stage. Forexample, if the cannula has four sensors A, B, C and D, then we wouldhave at least three sensing stages as follows: A-B, B-C and C-D.

Circuitry within the sensing module processes and modulates thesignal(s) from the cannula tube sensors and provide a drive signal to atleast one LED located on the module that enables the LED to changebetween steady red, yellow and green colors or between flashing red,yellow or green colors related to the positioning of the cannula eitherin or out of the patient's vein. The drive signal could also go to acontrol panel display or the like at the IV pole etc. or some other basestation that could have separate LEDs for the colors of red, yellow andgreen. A red color at each LED on a control panel display might indicatethe absence of blood in proximity to any one of the sensor(s) while achange in color to yellow and then to a solid green color for the LEDindicator would indicate the presence of blood being sensed at eachsensor stage on the cannula, which in turn indicates a proper insertionof the cannula within the patient's vein. The single or multiple LEDsare arranged in any logical pattern desired on the main control panel ordisplay back at the base station.

In a typical embodiment of the invention, a cannula tube includes atleast four sensors spaced apart a predetermined distance from eachother. Each sensor is embedded within the sidewall of the flexiblepolymer cannula tubing. Each sensor is spaced around the circumferenceof the generally tubular shaped cannula by approximately a 90 degreesrotational change between the first sensor at the distal end to thesecond sensor etc. such until a full 360 degrees change is reached fromthe distal end toward the hub end in the spacing of the sensors withinthe tubing. The first LED at the distal end shows a red signal as theblood is beginning to approach the sensor then it would start changingcolors from red to finally green indicating a blood flow across all foursensors and three stages of impedance level of the blood. Likewise, asthe blood begins to flow between the sensors the resistance and/orimpedance keeps dropping until the blood is across all four sensors andthe LED has changed to a solid green with the lowest resistance orimpedance level in all three stages. The doctor, intern, nurse or EMTwould then see the display change from red to yellow to green with theLED display on the module or on a control panel display providinginformation on whether the cannula tubing of the IV catheter is properlyinserted into the patient's vein as all four sensors are now detectingblood and the impedance is at the lowest reading.

Next, the four sensors are capable of being connected by thin wires orribbon conductors embedded within the soft plastic wall of the cannulatube leading back to the hub of the catheter and then onto the modulelocated on a forearm or back to a control panel at the base station. Themodule and the control panel are both capable of housing the electroniccircuitry for processing the signals from the sensor(s) and thengenerating a drive signal for changing the LED color on the module orfor selecting the correct colored LED on the control panel located atthe IV pole, IV Cart or other medical monitoring panel. The electroniccircuitry is also capable of generating a drive signal to an audiblealarm. The audible alarm with varying tones provides a means for thehealthcare professional inserting the catheter into the patient's veinto be guided during insertion of the cannula within the vein and tofurther indicate the status of a proper insertion of the cannula withinthe vein. The electronics required to process the signals and providethe output signal for the LED, LEDs or sound device are capable of beingplaced within a single ASIC or another miniaturized integrated chipcircuitry as shown in U.S. Pat. No. 7,169,107 which is incorporated byreference thereto or other similar miniaturized electronic integratedchip sets which a person having ordinary skill in the medical arts ofmonitoring patients is capable of assembling.

A method of inserting and monitoring the placement of a catheter tipwithin a peripheral vein on a patient body according to a preferredembodiment may include: inserting a cannula-over-needle apparatus intothe body, the apparatus including a cannula connected to an IV bag at ahub opposite a cannula tip; sensing various biological material withinthe body from detection circuitry connected to a sensor mounted on thecannula or at the hub; guiding the tip of the cannula corresponding tothe sensed biological material; stopping the insertion of the cannulainto the body when the sensed biological material is blood from withinthe peripheral vein; withdrawing and discarding the needle when the tipof the cannula is located properly within the peripheral vein;monitoring the status of the catheter tip within the peripheral veinfrom the cannula sensor: and generating an alert signal in the event thecatheter tip begins to withdraw from the peripheral vein in order toshut off the infusate.

The sensors used can be a single type or multiple types that are capableof detecting impedance or resistive changes when the blood is sensedwithin the vein by an impedance drop. For instance, a suitable sensortype might include bio-impedance, micro electrodes for resonanceimpedance sensing of human blood as set forth in Sensors and ActuatorsA: Physical Volumes 146-148, July August 2008, Pages 29-36 and presentedat the 14th International Conference on Solid State Sensors by authorsSiyang Zheng, Mandheerej S. Nandra, Chi-Yuan Shih, Wei Li and Yu-ChongTai in the Department of Electrical Engineering, California Institute ofTechnology, CA. USA, which paper is published by Elsevier and herebyincorporated by reference thereto. Other types of sensors that arecapable of providing signals include medical Telesensor ASICs withdetection of the blood reported back to the control panel by wirelesstelemetry. Very small medical Telesensor ASICS have been developed byOak Ridge National Laboratory. The sensors might use technologies likemagneto resistive, or micro-electro-mechanical systems (MEMES) sensors,acoustic sensors and others.

The above summary of the present invention is not intended to describeeach illustrated embodiment or every implementation of the presentinvention. The figures and the detailed description which follow moreparticularly exemplify these embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

This invention is explained in greater detail below in view of exemplaryembodiments shown in the drawings, wherein:

FIG. 1A shows a cannula with DC sensors made in accordance with thepresent invention completing a first stage insertion into a patientvein;

FIG. 1B shows a cannula with DC sensors made in accordance with thepresent invention completing a first stage and second stage insertioninto a patient vein;

FIG. 1C shows a cannula with DC sensors made in accordance with thepresent invention sensing a first stage, second stage and third stageinsertion into a patient vein;

FIG. 1D shows a cannula with DC sensors made in accordance with thepresent invention sensing a second stage and third stage insertion intoa patient vein with the first stage sensing the piercing of the veinwall and being outside of the vein into the surrounding tissues;

FIG. 2A shows a cannula with a single AC sensor made in accordance withthe present invention sensing proper insertion of the cannula within thevein;

FIG. 2B shows a cannula with a single AC sensor made in accordance withthe present invention sensing improper insertion of the cannula withinthe tissues surrounding the vein;

FIG. 3A shows a cannula with a single AC sensor and a conductive tracemade in accordance with the present invention sensing a state prior toinsertion within any vein;

FIG. 3B shows a cannula with a single AC sensor and a conductive tracemade in accordance with the present invention sensing insertion of thecannula into the tissues surrounding the vein;

FIG. 3C shows a cannula with a single AC sensor and a conductive tracemade in accordance with the present invention sensing proper insertionof the cannula into the vein;

FIG. 4A shows a flowchart where the cannula and circuitry areinitialized;

FIG. 4B shows a flowchart where the sensors of the cannula are atvarious stages during insertion into a peripheral vein of a patient inaccordance with the invention of FIG. 1A;

FIG. 4C shows a flowchart where the sensors of the cannula indicate anover penetrate through the vein in accordance with the invention of FIG.1A;

FIG. 4D shows a flowchart where the sensors of the cannula indicatewithdrawal failure detection and shut off flow of infusate in accordancewith the invention of FIG. 1A;

FIG. 5A shows a cannula with an acoustical sensor made in accordancewith the present invention prior to proper insertion within the vein inaccordance with the present invention of FIG. 1A;

FIG. 5B shows a cannula with an acoustical sensor made in accordancewith the present invention with proper vein insertion in accordance withthe present invention of FIG. 1A;

FIG. 6 shows a cannula with an acoustical sensor made in accordance withthe present invention with proper vein insertion including othermonitoring devices connected to the processing module which wirelesslytransmits signals to a base station display in accordance with thepresent invention of FIG. 1A;

FIG. 7A shows a cannula with an acoustical sensor made in accordancewith the present invention with proper vein insertion hardwired to acontrol panel and/or base station for processing and monitoring the veininsertion in accordance with the present invention of FIG. 1A;

FIG. 7B shows a cannula with an acoustical sensor made in accordancewith the present invention with proper vein insertion wirelessly sendingthe sensing signals to a control panel and/or base station forprocessing and display in accordance with the present invention of FIG.1A; and

FIG. 8 shows a cannula with an acoustical sensor made in accordance withthe present invention with proper vein insertion including othermonitoring devices connected to the processing module which wirelesslytransmits sensor and other device signals to a base station forprocessing and display in accordance with the present invention of FIG.1A.

DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention relates to an intelligent intravenous apparatusand method for guiding and detecting proper insertion of a cannula tipof a catheter into a vein for infusion of intravenous (IV) fluids andfurther monitoring and sensing when a withdrawal of the cannula tip fromthe vein occurs. B. Braun Intrusion Safety IV Catheter is an example ofa catheter that is capable of being modified to incorporate the featuresof the present invention. Various embodiments of the invention arecontemplated. One embodiment is illustrated in FIGS. 1A-1D. A secondembodiment is illustrated in FIGS. 2A and 2B. A third embodiment isillustrated in FIGS. 3A-3C. A fourth embodiment is illustrated in FIGS.5A, 5B, 6, 7A, 7B and 8. In all illustrated embodiments, the cannulaincludes one or more sensors that provide signals indicating whether ornot the cannula tip is properly inserted within a patient's vein orproperly withdrawn therefrom to avoid medical complications withinfusate. The broad principles of the invention are applicable to DC, ACand acoustical sensors with wires or wireless connections to electronicor electrical sensing module having signal processing and modulationelectronics therein attached to the patient or connected by either ahardwired connection or wirelessly back to a control panel and/or basestation that typical includes a computer with a monitor and keyboard.

As mentioned above, the first embodiment is illustrated in FIGS. 1A-1Dand includes a catheter 10 constructed in accordance with the presentinvention. The typical catheter 10 consists of a short polymer tube (afew centimeters long) inserted through the skin into a peripheral vein14 (any vein generally not inside the chest or abdomen). This is usuallyin the form of a flexible cannula 12 over-needle device, in which aflexible plastic cannula 12 comes mounted on a metal trocar (needle andtrocar not shown as already withdrawn from cannula 12). Once the tip ofthe needle and cannula 12 are located within the vein 14 the trocar iswithdrawn and discarded. The cannula 12 is further advanced inside thevein to an appropriate position and then secured with medical tape orthe like over a pair of plastic wings 20 secured to the tubing near aport or hub 22. An IV line 24 connects to the port or hub 22 through amale fluid input 26 that is inserted into the IV line 24. The IV line 24extends back to an IV Bag 28 containing the IV fluids 30. The IV Bag 28is hung on a hook 32 on an IV Pole 34 held upright by an IV Pole Standor Platform 36 having several wheel sets 38 attached thereto forportability of the IV Pole Stand 36.

Attached to the IV Pole 34 or Stand 36 or located at some otherconvenient place is a control and display panel 40. The control anddisplay panel 40 includes a computer or microprocessor circuitry forprocessing input signals from the sensors and then displayinginformation related to insertion of the cannula through the skin andinto a peripheral vein 14. Suitable circuitry adaptable to process theinput signals is shown in the FIGS. 1, 4, 6 and 7 and taught in thespecification of the U.S. Pat. No. 5,423,743 or is shown in FIGS. 1 and2 and taught in the specification of the U.S. Pat. No. 4,959,050 andboth are hereby incorporated by reference thereto. All of this circuitryis capable of being incorporated into a single micro integrated siliconchip or an application specific integrated chip (ASIC) in today'stechnology. Software required to program the ASIC and/or microprocessorcircuitry is well known by a programmer of ordinary skill in the art ofprogramming microprocessor and ASICS circuits. In fact, a person ofordinary skill in the art of programming is capable of writing numerousprograms to provide the desired results set forth in this application.There are probably thousands of different ways to create a softwareprogram that is capable of processing the signals from the sensors andthen generating a visual or audible alert to the end user of theapparatus and method in accordance with the present invention. Forexample, a simplified software programming would follow the logicdiagrams and/or flowcharts as shown in FIGS. 4A-D to program the ASIC ormicroprocessor circuitry located in the monitor module 48 on thepatient's forearm or back at the base station control panel 40. Amicro-computer with appropriate inputs and outputs with a softwareprogram therein could duplicate some portion of the circuitry shown in'743 and '050 patents for electrical circuits capable of using eitherdirect current (“DC”) or alternating current (“AC”) to power theguidance, monitoring and detection circuitry of the present invention. ATelesensor is capable of being used also. Medical telesensors areself-contained integrated circuits for measuring and transmitting vitalsigns over a distance of approximately 1-2 meters. The circuits of aTelesensor generally contain a sensor, signal processing and modulationelectronics, a spread-spectrum transmitter, an antenna and a thin-filmbattery.

Turning now to FIGS. 1A-D, the cannula 12 of catheter 10 includesbio-impedance, micro electrode sensors or even telesensors A, B, C and D(hereinafter “sensors”) embedded within the polymer or rubber during themanufacturing process of extruding the flexible plastic or rubbercannula 12 of the catheter 10. Thus in the preferred embodiment, thesmart IV cannula 12 includes multiple (4-6) conductive spots exposedfrom the tip to the midpoint of the cannula 12, and each conductive spotincludes conductive traces running back to the hub 22, and then eitherback to the control panel 40 or to a sensing monitor module 48 mountedby an adhesive backing on to the forearm 18 of the patient where the DCresistance and/or capacitance measurements are taken between themultiple spots or sensors A, B, C or D to determine whether the spots,and therefore the cannula 12, are in the vein 14 and bloodstream. Thisembodiment directly measures the conductivity within the bloodstream todetermine cannula 12 position within it. The sensors or conductive spotsA, B, C or D could also be mounted on the inner or outer surface of thecannula tubing 12 and then covered with a material bonded to the surfaceof the tubing 12. Also, as shown in FIGS. 1A-D, each sensor is connectedby a hardwired line or conductive trace 44 indicated by an arrow 42 ofany suitable conductor material to carry the extremely low level currentand voltage of the micro-electronic circuitry used to process thesignals back to the control and display panel 40 at the base station orback to a monitor module 48 on the forearm 18 for processing of theinput signals from the sensors.

As mentioned in the background of the invention, there are numerousscientific articles that discuss the ability to sense the conductivityof blood and thus its impedance. When the sensors or conductive spots A,B, C and D of the cannula 12 are in the top layers of skin 16 or withinthe subcutaneous tissues 17 surrounding the vein 14, the sensors wouldeach generate a high impedance signal output back to the control panel40 or module 48. In FIG. 1A, when the pairing of the sensors A and B(“first stage”) are within the vein 14, the impedance would be indicatedas being low on the control panel 40 at the base station. Meanwhile,when the pairings of the sensors B-C (“second stage”) and C-D (“thirdstage”) are still outside of the vein 14 and therefore not sensing thepresence of the blood then a high impedance would be indicated back onthe control panel 40 at the base station. Next, FIG. 1B shows the firstand second stages sensing the presence of blood within the vein 14 andso the pairings of A-B and B-C would both show a low impedancedetection.

In FIG. 1C, all three stages or pairings of A-B, B-C and C-D are sensingthe presence of blood so all three stages would show a low impedance onthe control panel 40 indicating a proper insertion of the cannula 12within the vein 14. If the medical technician pushed the cannula 12through the vein 14 as shown in FIG. 1D then the first stage or pairingof sensors A-B would show a high impedance indicating that the distalend 46 of the cannula 12 had passed through the vein 14 and had goneback out into the subcutaneous surrounding tissue 17.

Turning now to FIG. 2A, an IV cannula with a single conductive spot orsensor 56 near the tip or distal end 46, with a conductive trace 44running back to the hub 22, and thus to the sensing module 48 which isattached to the patient much like a conductive EEG pad. In this secondembodiment, a 50 kHz signal (or other suitable AC freq) is transmittedand received through the cannula at a very low current of 500 μA andvoltage by the sensing module 48. The signal impedance will varysignificantly when the cannula 12 is in the vein/bloodstream vsinsertion just under the skin 18 but not within the vein 14. The sensingmodule 48 further includes a soft switch or dome switch 50 to initiatethe smart IV catheter when it is first taken from its package. Or thesensing module 48 is initiated when the adhesive cover is removed whenthe catheter is taken out of its packaging and placed onto the forearm18. There is also an LED 52 and audible piezo horn 54 mounted within thesensing module 48 for providing guidance signals for the properinsertion of the cannula 12 within the vein 14. This makes the apparatus10 of the present invention totally portable for EMT usage in the field.The sensing module 48 mounted on the forearm 18 of the patient furtherincludes a battery power source to run the circuitry. Because the sensor56 is within the vein 14, a low impedance visual signal from the LED 52and/or an audible sound corresponding to low impedance visual alertwould be given by the piezo horn 54.

FIG. 2B shows the cannula 12 inserted below the top surface of the skin16 but not within the vein 14 so the impedance reading would be high asindicated on the monitor panel 40 and a corresponding color on thesingle LED 52 would blink or provide a steady red or flashing yellowcolor along with the audible signal from the horn 54 corresponding tothe LED pattern of colors.

FIGS. 3A-C shows a third embodiment which is another version of thesecond embodiment but further includes wireless transmission by eitherBluetooth or WiFi 59 to a computer base station 60 in which theconductive spot or sensor 56 at the tip of the cannula 12 is followed byan exposed, partially conductive trace 58 extending toward the hub 22for about a centimeter or more on the cannula 12. This will increase theresolution of the signal measurement when the cannula tip 46 is eitherpushed through the vein, or has begun to withdraw from the vein. Thisembodiment is a wireless version of either the AC or DC circuitrypreviously described. The computer base station 60 would allow for amore sophisticated programming of the overall systems incorporating thesmart IV catheter for guiding the medical professional when insertingthe cannula within a vein 14 of the patient. For example, partiallyconductive trace would allow a variation of colors to be used with theLED visual indication of the progress being made by the medicalprofessional. The colors of red 52 a, yellow 52 b and green 52 c areshown on the sensing module 48 but other colors might be used too whenusing the computer 60 with a monitor 62 allowing the use of manydifferent colors to match the stage of progress during the insertion ofthe cannula tubing 12 within the forearm and guiding inside of the vein14.

For example, in FIG. 3A the cannula tubing 12 is above the skin 16 so ared LED 52 a is visually displayed on the sensing module 48 and then onthe computer monitor or screen 62. FIG. 3B shows a partial insertion andthe colors of red 52 a and yellow 52 b may be visible by the LEDs on thesensing module 48 and on the computer monitor 62. Finally, in FIG. 3C,the cannula 12 is properly inserted within the vein 14 and the steadycolor of a green LED 52 c is visible on the sensing module 48 and thenlikewise on the computer monitor 62.

For the second and third embodiments, the smart IV catheter of thepresent invention uses bioelectric impedance to monitor infiltrationusing a 50 KHz signal at 500 μA. This high frequency signal at lowamperages is similar to handheld AC devices made by Tanita and OmronCorporation in U.S. Pat. No. 7,039,458 and U.S. RE 37954 that operatesomewhat similar but are totally different in functioning and method.

FIGS. 4A-D shows simple flowcharts for the operation of the smart IVcatheter. Turning now to 4A, when a portable catheter 10 made inaccordance with the invention is taken out of its packaging with theattached sensing module 48, the user removes the adhesive backing cover,which turns on the power and initializes the circuitry of the module 48.Alternatively, the soft button 50 is pushed to power on/initialize thedevice. First, the DC version of embodiment of the device first checksthe three stages and the sensors thereof to make sure the impedance ishigh for all three pairings of sensors. The LEDs preferably flash in asequence of green, yellow and red to indicate a good device. Optionally,the piezo horn provides three short tones to indicate that the catheteris not functioning properly. In the AC version, a check of the impedancecannula emitter (TX) to base (RX) is done which should show a highimpedance when initialized.

FIG. 4B show the steps when insertion is being done by the medicalprofessional. There is a monitoring resistance/capacitance/impedance attip or tip plus trailer A-B, B-C and C-D. A-B flashes green/yellow LEDcolors and a tone of two long tones is emitted. If there is A-B plus B-Cthen the LEDs flash green, green and yellow. And finally, if there isA-B, plus B-C, plus C-D flash solid green with a continuous tone for apredetermined count and then stop to preserve the battery.

FIG. 4C shows an overpenetration through the vein. In the DC version ofthe device, the A-B resistance increases as it passes through the veinand the B-C and C-D stages continue indicating a low impedance. Thedevice then creates an alert to the medical professional with the LEDflashing red-red and an audible tone indicating failure occurs so thatIV fluids may be stopped. In the AC version, the spot or sensor at thetip increases in impedance while the trailer conductive strip is stilldecreasing or is steady.

In the final flowchart, FIG. 4D deals with the situation when there is awithdrawal failure detected and a shut off of the infusate needs to beinitiated. Here as the cannula pulls out of the vein, in the DC versionthe last stage C-D opens briefly and remains different from B-C and A-B.An LED display of green, yellow occurs. Then as B-C opens briefly, itwill differ from A-B and flashes similar to C-D with a flash of green,yellow and yellow. And then when A-B opens briefly, it matches B-C andC-D. Then the alert on the display becomes a solid red color on the LEDwhile three short audible tones are repeated indicating a failure hasoccurred with the withdrawal of the cannula tip from the vein.

In FIGS. 5A-B, a fourth embodiment shows the use of an acousticalsignature for the apparatus and method to continuously monitor that thecannula 12 is remaining properly inserted within the vein 14 inaccordance with the present invention. The cannula 12 includes anacoustical transducer 64 of a broadband 25 to 50 MHz type well known inthe art such as the medical transducers manufactured and sold by GeneralElectric Company of Schenectady, N.Y. The transducer 64 is placed at aposition along the cannula 12, such as near the tip 46 of the cannula12, within or on a hub 22 at an end opposite the tip 46, or in or on thecannula in between the tip 46 and the hub 22, such that a largeamplitude echo signal from the transducer 64, 64′ is continuouslymonitored to indicate the correct tip placement of the cannula tubing 12within the vein 14. In one embodiment of this invention, the transducer64, 64′ is angled with respect to the cannula 12 in an insertiondirection, such as having an emitting and/or receiving sensor componentor surface disposed at 45-90° relative to the longitudinal axis of thecannula 12.

As shown and described, transducer 64, 64′ may be positioned within thecannula 12 as shown in transducer 64 or, alternatively, upstream of andexternal to the cannula 12 such as shown in transducer 64′. In oneembodiment, the transducer 64, 64′ is positioned upstream from the tip46 so that the transducer 64, 64′ is not beneath the skin 16 uponinsertion of the tip 46, and can be placed in the upper 75%, desirablythe upper 50%, and preferably the upper 25% of the cannula 12. In onepreferred embodiment, the transducer 64, 64′ is placed at, either on orwithin, the connecting hub 22. As such, transducers 64, 64′ shown inFIG. 5A are intended to show two alternative feasible placements for usein the subject system. If suddenly a smaller amplitude echo signal fromthe transducer 64, 64′ is detected then this provides an indication thatthe tip of the cannula 12 of the catheter 10 is withdrawing from thevein 14 into the subcutaneous tissue surrounding the vein.

Most high frequency transducers for medical applications are made from athin piezo-electric polymer film. The transducing element 64, 64′ ismounted within the cross section near the cannula tip 46 or upstream ofthe cannula tip 46, respectively. A coaxial cable 66 within the crosssection of polymer cannula 12 connects the transducer to an externalsignal source. Electrical signals are transmitted to and received fromthe ultrasonic transducer 64, 64′ via the coaxial cable running thelength of the cannula and out the hub area 22 back to either the signalprocessor in the sensing module 48 or the base station control panel 40.The external signal source for the ultrasonic transducer is well knownin the art. The control panel screen or the LED(s) on the sensing module48 provides a display for the received transducer signals to monitor theplacement of the tip 46 of the cannula within the vein 14.

FIG. 5A further shows that the cannula is through the outer surface ofthe skin 16 but not yet within the vein 14 so the acoustical signatureecho generated is small in amplitude due to the dense nature of thenormal tissues rather than a greater amplitude echo signature when thetransducer 64, 64 is within a bloodstream of the vein 14. On the otherhand, FIG. 5B shows the cannula 12 and within the vein 14 and the echosignature picked up from the distal end 46 of the cannula tubing 12 isgenerating a larger amplitude echo signal for indicating that the tip ofthe cannula tubing 12 is properly secured within the bloodstream of thevein 14. The magnitude of the echo signature is then either displayed onthe screen of the control panel 40 or indicated by visual and/or audiblesounds on the sensing module 48. In summary, when the cannula 12 isoutside of the vein 14, the amplitude echo signal generated by thetransducer is small and when the cannula 12 is within the vein andsensing the bloodstream, the echo signal is large.

In FIG. 6, the cannula 12 is properly inserted within the vein 14 withthe acoustical signature being used with a sensing module 48. Also, apulse oximeter 68 which is a non-invasive method allowing the monitoringof the oxygenation of a patient's hemoglobin is connected to the indexfinger 69 and its output signal is connected via a conductor 70 to aninput terminal 72 to the sensing module 48. Moreover, the sensing module48 might have other inputs such a blood pressure monitoring input. Theunique feature also shows that the sensing module 48 is sending back itssignal of the smart IV catheter 10 insertion plus information from thepulse oximeter 68 wirelessly to the base station control and displaypanel 40.

FIG. 7A shows an acoustical signature device that includes a hardwireconnection back to the control and display panel 40. FIG. 7B shows anacoustical signature device that includes a wireless transmission backto the control and display panel 40. Both devices as shown in FIGS. 7A-Bfunction as previously described for the devices shown in FIGS. 5A-Babove for the apparatus and method in accordance with the presentinvention.

According to the embodiments shown in FIGS. 5-7, IV infiltration occurswhen the cannula 12 pulls out of the vein yet remains under the skin.The embodiments shown in FIGS. 5-7 may further detect and identifyocclusions as described below. Occlusion occurs when the cannula 12remains in the vein, properly placed, but starts to accrete bloodplatelets at the orifice of the tip. This blood clot accretion at theorifice of the tip slowly closes off the tip to any fluid flow. Whenthis occurs, the medical professional often has to pull The IV and run anew one, an expensive and often painful inconvenience. Medicalprofessionals have to watch for occlusion indications and keep thecannula 12 open by pushing saline through the cannula or Heparin, ananticoagulant.

According to a preferred embodiment, the sensing module 48 and/or thedisplay module 40 may be tuned in such a way as to detect a reduction inreturn echo strength from the acoustical transducer 64, 64, so as todetect occlusion in process before it fully closes the tip of thecannula 12. With a desired acoustical transducer 64, 64′ and softwareanalysis capability, movement of the cannula 12 within the vein (termeda “trombone effect”) and occlusion of the tip of the cannula 12 may besensed and detected.

FIG. 8 shows the wireless connection back to control panel 40 in whichthe pulse oximeter 68 is connected from the index finger 69 back to thesensing module 48 and further may include a blood pressure input to thesensing module 48 (not shown). In addition, the sensing module furtherincludes a reflective pulse oximeter 74 mounted within the sensingmodule 48 that shines down into the hand from the backside of thesensing module 48 for its measurements, includes bright red, yellow andgreen LED lights to show the various stages of operation of the devicecovered by the apparatus and method claims.

As noted above, the present invention is directed generally to a medicaldevice and more particularly to an electrical signal-guided catheterwith sensors embedded in the polymer skin of a flexible plastic cannulato sense the presence of the bloodstream for proper insertion of thecannula tubing within a peripheral vein to administer IV fluids. Theelectrical signals corresponding to the sensing of subcutaneous tissueand the bloodstream within a vein provide an electronic signalvisualization of the placement through the skin and subcutaneous tissuesinto the vein and further including a method to locate the flexiblecannula within the vein for correct catheterization. Secondly, thiscatheter detects any improper withdrawal of the catheter from the veinand thus a leakage into the subcutaneous tissues indicating aninfiltration condition.

According to one preferred embodiment of this invention, the smart IVcannula 12 as shown and described may further include a superhydrophobiccoating and/or construction. Accordingly, the cannula 12 may include atleast one of: a micro- or nano-coating over and/or within the cannula12; the cannula 12 may be constructed or Teflon® or silicone; and/or ahybrid construction, such as silicone oil impregnated urethane.

A suitable micro- or nano-coating may comprise a coating such asdescribed in U.S. Pat. Nos. 8,574,704 and 8,535,779 to Smith et al.,which are hereby incorporated by reference. The Smith et al. patentsdescribe non-wetting surfaces that include a liquid impregnated within amatrix of micro/nano-engineered features on the surface, or a liquidfilling pores or other tiny wells on the surface. Such a product, calledLiquiglide™, may be used to coat the cannula 12 described herein. Asdescribed, a micro/nano-engineered surface coating enables a durableliquid-impregnated surface coating to be placed over the full exteriorand interior surfaces of an IV cannula 12.

Alternatively, the cannula 12 may be constructed of a non-stick materialsuch as Teflon® or silicone. The cannula 12 may be wholly constructed ofsuch material or partially constructed, coated and/or reinforced withsuch material.

According to another alternative of the subject invention, the cannula12 may comprise a hybrid construction that includes a hydrophobiccoating impregnated within or coated over and around a non-stickconstruction. Such, hybrid construction may include a silicone oilimpregnated urethane construction.

A benefit of such liquid-impregnated surface coating or alternativelydescribed constructions is to inhibit the initial “seed” adhesion ofblood protein fibrin to the cannula surface, thus preventing furtherfibrin accretion at the orifice of the tip of the cannula, thuspreventing IV cannula occlusion.

The present invention should not be considered limited to the particularexamples described above, but rather should be understood to cover allaspects of the invention as fairly set out in the attached claims.Various modifications, equivalent processes, as well as numerousstructures to which the present invention may be applicable will bereadily apparent to those of skill in the art to which the presentinvention is directed upon review of the present specification. Theclaims are intended to cover such modifications and devices.

What is claimed is:
 1. An intravenous catheter for guiding tip placementinto a peripheral vein, comprising: a flexible, tubular cannulaincluding an insertion tip that is insertable into a peripheral vein; asensor mounted external of the cannula for sensing and then generatingan output signal representative of a sensed biological materialincluding blood at the insertion tip of the cannula, wherein the sensorcomprises an acoustical transducer; a processor circuitry connected tothe sensor output signal for receiving and then generating a display;and wherein the display provides a feedback to a medical personnel ofinsertion tip placement during transition into, placement within, andwithdrawal from the peripheral vein of a patient body.
 2. The inventionof claim 1, wherein the sensor generates an amplitude echo signaturesignal within the cannula when energized.
 3. The invention of claim 1,wherein the sensor is embedded at an angle to a longitudinal axis of thecannula.
 4. The invention of claim 3, wherein the sensor comprises apiezo-electric polymer film sensor
 5. The invention of claim 1, whereinthe predetermined location is outside the vein when the cannula tip isinserted.
 6. The invention of claim 1, further comprising a cableembedded within a hub of the cannula and connecting the sensor to theprocessor circuitry.
 7. The invention of claim 1, wherein the sensor ismounted at a hub adapted to attach the cannula to an IV bag.
 8. Theinvention of claim 7, wherein the processor circuitry is connected tothe sensor at the hub.
 9. The invention of claim 7, wherein feedbacksignal comprises a first signal during skin penetration, a second anddifferent signal after skin penetration, and a third and furtherdifferent signal upon the proper insertion of the cannula within theperipheral vein.
 10. The invention of claim 9, further comprising adifferent color light signal for each of the first signal, the secondsignal, and the third signal.
 11. The invention of claim 1, wherein thecannula comprises a liquid impregnated surface.
 12. The invention ofclaim 1, further comprising a hydrophobic micro-coating or nano-coatingcoating the cannula.
 13. The invention of claim 1, wherein the sensor isa telesensor for wirelessly transmitting and receiving signals from theprocessing circuitry.
 14. The invention of claim 1, further comprisingan LED display corresponding to the sensed biological material in thebody.
 15. An intravenous catheter for guiding tip placement into aperipheral vein and monitoring the tip removal from the peripheral vein,comprising: a flexible plastic, tubular cannula having a tip at a distalend for insertion into a peripheral vein of a body and a hub at theopposite end for attachment to an IV bag including an infusate; a sensormounted at the hub for sensing the impedance of a sensed biologicalmaterial in the body including the blood and then generating an outputsignal representative of a sensed biological material, wherein thesensor comprises an acoustical transducer that generates an amplitudeecho signature signal when energized; and processor and modulationcircuitry connected to the output signal and that receives and thengenerates a display or audible sound representing the location of thecannula tip within the biological material being sensed in the bodyduring insertion of the cannula or upon the withdrawal of the cannulafrom the body.
 16. The invention of claim 15, wherein the displayprovides a feedback to a medical personnel upon correct catheter tipplacement in the peripheral vein of the patient and wherein the displayor audible sound provides an alert to shut off the infusate when the tipdislodges from the vein but remains in the body to avoid infiltrationinto the subcutaneous tissues of the body.
 17. The invention of claim15, wherein further including a sensing module housing the processor andmodulation circuitry having an adhesive backing for attachment to theskin of the body in near proximity to the catheter.
 18. The invention ofclaim 17, wherein the sensing module further includes Bluetooth or WiFicircuitry for wirelessly communicating to a base station control anddisplay panel for assisting in the insertion of the catheter tip in thevein and then subsequently monitoring the tip within the vein to detecta withdrawal of the tip from the vein.
 19. The invention of claim 17,further including a pulse oximeter connected to the index finger havingan output signal connected to an input port on the sensing module,and/or a reflective pulse oximeter on the adhesive backside formeasuring the oxygenation of the hemoglobin in a bloodstream within thevein.
 20. A method of inserting and monitoring the placement of acatheter within a peripheral vein on a patient body, the methodcomprising: inserting a cannula-over-needle apparatus into the body, theapparatus including a cannula connected to an IV bag at a hub opposite acannula tip; sensing various biological material within the body fromdetection circuitry connected to a sensor mounted at the hub, whereinthe sensor is an acoustical transducer generating an amplitude echosignature signal when energized; guiding the cannula tip correspondingto the sensed biological material in the body; stopping the insertion ofthe cannula into the body upon receiving a proper insertion signal whenthe sensed biological material is blood from the interior of theperipheral vein; withdrawing and discarding the needle when the cannulatip is located properly within the interior wall of the peripheral vein;monitoring the status of the cannula tip within the peripheral vein fromthe cannula sensor; and generating an alert signal in the event thecannula tip begins to withdraw from the peripheral vein in order to shutoff an infusate.